Computers have ushered in the Information Age: With their ability to manage and process large amounts of data, the ability of the user to perform mundane tasks has been enhanced, and activities which were previously impossible are now commonplace. As computers have become more sophisticated, the tools and options at the disposal of the user have increased. For example, video browsing and, more generally, multimedia browsing are now commonly performed over the Internet or on local systems and networks such as a company's Intranet. Browsing may be conducted for any number of purposes, including entertainment, education (such as distance learning), or accessing the news.
Information in written form, such as a book, generally includes a table of contents and/or an index which permits the user to quickly evaluate the book's content and/or relevance to the user's interests. Browsing a book can be done quickly by simply flipping through the pages. Video browsing, on the other hand, while providing a number of advantages to the user, can be a very time consuming and frustrating process. Browsing a video to get an overview of its content is not generally time efficient. It may involve playing certain segments of the video and then fast forwarding or skipping to points of potential interest. This is especially time consuming in the case of an analog recording medium such as a tape, but even with digital recording media, the user must still take the time to watch various video segments.
To address these concerns, various techniques for summarizing video in a more compact form have been advanced. The use of “storyboards” is one such technique, in which a table of keyframes selected from the video are presented, possibly along with text or other “static” or stationary information. “Moving storyboards”, or slide shows, are media streams which take the storyboard technique a step further by presenting a series of stationary images along with audio. “Fast playbacks”, in which the video is fast forwarded, and “video summaries” (“video skim”), in which key video segments are presented, are two other video visualization technologies for more compactly presenting audiovisual information. “Talk presentation”, in which video, audio, and speaker's slides play together in one or more windows, is another visualization technology. These and other possible representations of the original video are referred to herein as different “views” of the video.
U.S. Pat. No. 6,166,735 to Dom et al. (“Video story board user interface for selective downloading and displaying of desired portions of remote-stored video data objects”) and the article “What is in that video anyway: in search of better browsing” (S. Srinivasan et al., 6th IEEE International Conference on Multimedia Computing and Systems, Jun. 7-11, 1999, Florence, Italy) are concerned with switching from a (static) storyboard to the corresponding video. When the user selects a keyframe in the storyboard, the video starts to play from a point in the video corresponding to the selected frame. This technology relies on the use of static links with offsets, in which the offsets do not depend on when the user selects the keyframe of interest. Furthermore, with this technology, the user cannot switch back from a point in the video to a corresponding point in the storyboard (i.e., the linking is in one direction only). This method does not allow switching from a first media stream to a second, related media stream beginning at a point in the second media stream which corresponds to the point in the first media stream where the first media stream was playing when the user made his or her selection. Thus, with this approach, the ability of the user to switch back and forth between a video and its related views is limited and not satisfactory. In particular, the user is frustrated since a compact view is not synchronized with its corresponding full length video or with other views. Thus, by way of example, switching from a point in a video summary to the corresponding point in the full video is currently not supported. What is needed is a system that provides a way of directly switching between different views, or more generally between different media streams, such that the point at which a media stream is entered corresponds to the point at which the previous media stream is exited.